they already tried that bro.... cng mechanic knob guma ker set krnay ki koshish kertay han... for the time rpm 900 p set to ho jata ha per jab engine switch off ker k on kertay han to vohi 500 p a jata ha.... second jab rpm ko throtle body se increase krvata hon to petrol p start hotay time rpm 2,500 tak chala jata ha... (risky for cold engine),,,, agar ye sari setting rehnay b doon to jab cng p AC off kerta hon to rpm 2,000 per still ho jata ha....